I know this has been asked before, but can we suggest a new approach to handling this problem. For example making new users accept an answer to the very first question they ask so they get the picture that they need to accept answers. By allowing them to continue they end up posting sometimes up to 5 questions in a few days and end up letting them sit there after they get a few answers. There has been a surge in answered questions that have not been accepted in the last few weeks which really messes up those who put time into answering them (me included). There should be increased messages and alerts to those who don't accept answers. And maybe once they reach a certain milestone in reputation these messages stop being displayed as much.
I also noticed that most of these users come from forums that obviously don't work off the same system Stack does, so could these messages be displayed when ever they visit their question to remind them that this is the way it works around here.